Steam rinse sterilization processes are often used on bottles and other containers, including those made of HDPE and other polymers. Such sterilization processes, for example using a WAB peroxide steam rinser, often result in the bottles reaching temperatures of 75-85° C. This temperature coincides with the glass transition temperature of PET, as shown in FIG. 8, and the modulus of PET changes rapidly throughout this temperature range, as shown in FIG. 9. As a result, the physical stability of PET bottles decreases and becomes unpredictable and inconsistent, resulting in shrinkage and/or deformation of the bottles. Thus, the use of PET bottles in steam sterilization processes can present difficulties. The use of recycled PET (rPET) increases the unpredictability and inconsistency of the physical properties, as the intrinsic viscosities of recycled materials typically exhibit greater variation. Additionally, certain deformation characteristics are more difficult to control in square or other non-cylindrical bottles, and controlling shrinkage of the bottle becomes more important as a result.
The present device and method are provided to address the problems discussed above and other problems, and to provide advantages and aspects not provided by prior bottles and other containers of this type. A full discussion of the features and advantages of the present invention is deferred to the following detailed description, which proceeds with reference to the accompanying drawings.